I think I got it, its a mushroom vent, uesd for attic or toilet venting, there are stainless steel ones used on boats. I noticed there were a few posts on this vent so maybe this will help others, when I pick one up i will up load a few pictures of the new on. going to look for the stainless one, I broke this one with the snow shovel this last winter because we got a little more than 134 inches of snow. note to self build boxes this fall for all the vents.